1. Field of Invention
The present invention relates generally to audio processing and more particularly to post acoustic echo cancellation filtering in an audio system.
2. Description of Related Art
Conventionally, when audio from a far-end environment is presented through a loudspeaker of a communication device, a far-end audio signal may be picked up by microphones or other audio sensors of the communication device. As such, the far-end audio signal may be sent back to the far-end environment resulting in an echo to a far-end listener. In order to reduce or eliminate this echo, an acoustic echo canceller may be utilized.
However, there may be some residual echo remaining after acoustic echo cancellation is performed. This is a result of the fact that there is some limit to the amount of echo that can be subtracted out from an acoustic signal picked up by the microphones or audio sensors. Typically, what is left is still audible. In order to reduce or eliminate the residual echo, a non-linear processing or postfiltering process may be utilized after the acoustic echo cancellation operation. Conventionally, these non-linear or postfiltering processes require knowledge of the far-end audio signal that is leaking back through the microphones or audio sensors.